Calcium cyanamide manufacture
Limestone, coal and atmospheric nitrogen are the natural raw materials from which calcium cyanamide is manufactured. Regular investment and constant improvement of the production process ensures a modern, efficient and environmentally friendly manufacture of the specialty fertilizer.
Calcium cyanamide is manufactured in three stages:
- Stage one: Manufacture of burnt lime (also known as quick lime)
Limestone (CaCO3), mined from natural deposits, is crushed and then processed in coke or oil-fired furnaces to form burnt lime.
- Stage two: Manufacture of carbide
The burnt lime obtained as a result of this process is fed into carbide furnaces together with coke and anthracite, which provide a supply of carbon. Calcium carbide is produced in these ovens at temperatures above 2,000°C, with electrical energy generating the heat required. The carbon monoxide generated during this manufacturing process is collected and used as a starting material for further chemical reactions.
- Stage three: Manufacture of calcium cyanamide
In the last stage of the synthesis nitrogen gas is passed through finely-ground calcium carbide which has a temperature of approx. 1,100°C. This chemically binds the nitrogen, resulting in calcium cyanamide. The carbon released during this reaction gives the calcium cyanamide its black color. The nitrogen gas necessary is recovered in a proprietary air separation plant using the Linde method.
The so-called technical calcium cyanamide coming from the rotary kilns is further processed for use in agriculture and horticulture. The ground-calcium cyanamide is produced by finely grinding the product. PERLKA® (= pearled calcium cyanamide) is produced from the ground product by granulation, and adjusted to the defined grain size by sieving.